I'm in the process of making some Bendmaster Deluxe fine tuners out of a 4mm allen head bolt and some kneadable epoxy; it's a bit of trial and error but the same principle would apply to making the knobs - it's the tapered ones you're after, eh? Do you know any modellers in Leicester? You know; the guys who build house sized model railways from scratch; they're good people to know!!Keep an eye on the auction sites, as well; sometimes they turn up, even a wrecked guitar can occasionally yield bits....

_________________FWIW, an after market esoteric nut is a solution to a problem that doesn't exist, and a great way to convert your money into someone else’s.